Concentric circles evenly spaced in UV mode
ok the answer was pretty hard to find :P so what you basically wana do is to have a uv consist of concentric circles .This could be done if you select all the inner rings except the vertice at the mid of the concentric uv map and smooth them.But this can't be done in blender..... So what I did was to create 2 shape keys a key with the original mesh and an other one in which I smooth out all the inner rings (except the vertice in the center of the mesh).Then Uv unwram it and change the shape key value and you got it ! (I will upload a blend file with an exaple)
Also be sure to set the options so you achieve maximum smoothness 


Edit: If you have many edje rings and dont want to select them by hand you can do
this:


So what you can do to select the rings is:Create a new shape key and transform your mesh similar to mines*(orange arrow) (note the red circle options) .Then do the options that are pointed with pink (you should change to ejde select mode purple) and after you click the option that the pink arrow is pointing you will have ALL the edje rings selected.

*What I did was to grab the midle vertice and pull it up